The cannabis plant (Cannabis sativa L.) (“cannabis”) has a long history of being used for medicinal and recreational purposes. Cannabis plant material contains a variety of chemical compounds, including those responsible for the “high” associated with cannabis consumption as well as other physiological effects. Among the compounds present in cannabis are tetrahydrocannabinolic acid (“THCA”) and tetrahydrocannabivaric acid (“THCVA”). While THCA and THCVA themselves produce few physiological effects when directly ingested, exposing THCA and THCVA to high temperatures, such as those produced when cannabis burns during smoking, causes those compounds to undergo decarboxylation reactions to form psychoactive or other physiologically active compounds. THCA, in particular, is well-known for its conversion via decarboxylation to Δ9-tetrahydrocannabinol (“Δ9-THC”), which is psychoactive. Upon heating, THCVA undergoes a similar decarboxylation reaction to form tetrahydrocannabivarin (“THCV”), which has appetite-suppressing effects.
As of February 2019, ten U.S. states have legalized the recreational use of cannabis, and thirty-two U.S. states have legalized the use of cannabis for medicinal purposes. As the state-level legalization of cannabis has expanded, so has the production of cannabis-derived products. Cannabis extracts (sometimes known as “cannabis oils”) have emerged as an important category of cannabis-derived product. Cannabis extracts are produced by subjecting cannabis to an extraction process, wherein solvents are used to dissolve (“extract”) chemical compounds from harvested cannabis plant material.
In existing methods of making cannabis extracts, harvested cannabis or cannabis extract may be heated in an oven to achieve the decarboxylation of compounds, such as THCA and THCVA, to form psychoactive or physiologically active compounds, such as Δ9-THC and THCV. A major drawback of oven-based decarboxylation is the tendency to cause the loss of desirable volatile compounds, such as caryophyllene and other terpenes, through evaporation or heat-induced chemical reactions. Accordingly, a process is needed to enable a greater degree of control over the decarboxylation of cannabis extracts.